Details

Autor(en) / Beteiligte

• An, De-Lie
• Zhang, Ying-Jun
• Chen, Qiang
• Zhao, Wen-Ying
• Yan, Hong
• Orita, Akihiro
• Otera, Junzo

Titel

Enantiopure Double-Helical Phenylene Ethynylene Cyclophynes with the 2,2′-Binaphthyl Template

Ist Teil von

• Chemistry, an Asian journal, 2007-10, Vol.2 (10), p.1299-1304

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2007

Quelle

Access via Wiley Online Library

Beschreibungen/Notizen

• New types of enantiopure compounds were synthesized to gain better insight into the structural features of phenylene ethynylene cyclophynes. Besides the previously obtained meta‐substituted arylene ethynylenes, 1, ortho‐connected phenylene ethynylene units were incorporated to give cyclophynes with ortho/meta and ortho/ortho connection modes, 2 and 3. Furthermore, a diphenylethyne component was also accommodated in 4. Both ab initio calculations and NMR spectra suggest a large amount of strain for 2 but less strain for 3 and 1 a, the latter having the smallest ring size among cyclophynes with the meta/meta connection mode. The CD spectra of 2 and 3 showed a characteristic shoulder at around 340 nm, similar to the case of 1 a. This implies that the aromatic acetylene bonds cross over each other in the double‐helical structure. These results indicate that chirality information is useful for probing the persistency of molecular shape. Going over and under: Double‐helical phenylene ethynylene cyclophynes with various connection modes on the phenylene bridge can be synthesized in enantiopure form. NMR and CD spectroscopy, together with molecular‐orbital calculations, help elucidate the shape persistency of these molecules.